The invention concerns a bearing construction for a crankshaft such as the type employed in a cold Pilger rolling mill for the rolling of tubes, the connecting rods of which are each mounted in a split plain friction or sliding bearing which is provided with an abrasion bushing made of surface hardened steel and a bearing box made of high-load or strength synthetic material which bearing box furnishes the frictional surface and is provided with lubricating compartments, whereby in each case the joints of the bearing boxes are arranged at right angles to the major axis of the crank assembly and the lubricating compartments and their lubricating holes are located in the vicinity of the joints of the abrasion bushings and the cooling fluid used for rolling in the cold pilger rolling mill is used for lubricating the frictional surfaces.
It is to be appreciated that the bearing construction disclosed herein is used for connecting the connecting rod of a crankshaft to the roll housing of the pilger mill similar to that shown in U.S. Pat. No. 3,890,821. It is to be further noted, however, that this bearing construction could also be used to connect the other end of the rod to the crank, i.e. the rod to the end of the crankshaft itself.
A bearing construction of this sort mentioned above is described in German Patent Application No. P 30 13 135.2. With the proposed solution, a bearing construction is provided for a cold Pilger rolling mill, in the case of which an abrasion of the crankshaft is for the most part avoided by the fact that, as a result of the special bearing construction, the cooling fluid which is used for rolling in the cold pilger rolling mill can be used for the lubrication of the friction bearings. Consequently, the known problems are eliminated which arose as a result of the fact that a mixing of coolant and lubricant occurred in traditional bearing, which mixing brought about a high abrasion of the crank or, as the case may be, crankshaft mounting, despite the fact that there was also a thorough filtering of abrasive impurities.
An essential task of the cooling fluid for the proposed bearing construction is the removal of the heat of friction. Since a hydrodynamic lubrication cannot be achieved in the case of the bearing construction selected and since constant friction is present, particular attention must be devoted to the removal of heat. In this context, the particular construction of the lubricating grooves and lubricating compartments often does not suffice for the removal of heat by way of the cooling fluid.